This tool may be used to load an Atari executable file, stored on the PC,
into a real Atari computer, via the SIO2PC interface.
Only data input and data output lines are used, so X-LOAD should work
with all types of the interface.
It is experimental version. I'm not sure if it will work
with every hardware. I've noticed it is not stable and sometimes
transmission can hang or distortions in loaded data may appear.
The reason is that there is no error-checking, while transmission is
fast (57.6 kbits/sec).
CHANGES
Version 1.1
files with no explicit run address are started from the beginning
of the first block
Version 1.0
first release
USAGE
You should pass as the parameters the executable file name and optionally
the options:
/1 - /4
Serial port number. Default is 2.
/p
Force using 'professional loader', which allows you to load code/data
into the RAM under ROM ($c000-$ffff) and starts the program with disabled
ROM and interrupts. By default, standard loader is used, which can load
any Atari executable not demanding DOS or any special loader.
After you run X-LOAD, you only have to boot your Atari and the program
will be loaded and run.
While loading, PC prints memory locations, which the program loads into.
After the program is loaded and run, X-LOAD terminates. You may exit it
earlier at any time by pressing the ESC key.
DETAILS
First, X-LOAD sends a byte to Atari and then waits until the Atari is booted.
The byte can be used to detect from Atari, that PC is ready for transmission.
When you are testing your program, you may code periodic checking
if a byte was received, and performing cold reset in that case.
So you don't need to touch your Atari to run your program on it.
While booting, X-LOAD accepts two commands for disk drive 1:
'S' - read status. Used by the Atari OS to check presence
of a disk drive.
'R' - read sector (only first). Used to transfer the loader.
After the Atari receives and runs the loader, the transmission runs at 57600
bits/sec.
The transmission protocol is very simple: Atari sends a byte to inform that
it is ready for receiving data. Then PC sends a 3-byte header and a block
of data. First two bytes of the header are the high and the low byte of the
address of the last byte in the block minus $ff. Third byte equals low byte
of ($100-block_length). Then come block data, which are loaded directly
into their memory locations.
For more details, view source files of the loaders:
You may have noticed that X-LOAD is somehow similar to X-BOOT, which also
has two loaders. The main difference is that X-BOOT loaders use system
routines to get sectors at regular speed of 19200 bits/sec.
They use sector buffer and require some low memory locations not to be altered
because of Atari operating system. In this respect X-LOAD loaders are better,
because they allow loading into whole memory except for the loader code.